My first time playing? I can't remember exactly since it was like 6 years, but I think past me tried to overlevel and my gang were around the 60s I think?
During my Black nuzrun? I just kept it simple at like level 52 or so. Unlike in other games in BW1 you could take a break after the E4 to do other things like grind for the champion, so yeah. I did lose my Archeops against the Fighting E4, though I admit it was my fault. Thankfully my bro-tier Chandelure prevented anymore deaths from the E4.